1. Field of the Invention
The present invention is directed to optical systems for the realization of a full color projection display employing reflective light valves.
2. Discussion of the Prior Art
There is interest in very high resolution displays for work stations, multimedia, medical and other applications. In particular, projection displays using spacial light modulators or reflective light valves, for example, of liquid crystal type, have the potential for producing a display of resolution performance beyond that available from CRT's.
U.S. Pat. No. 5,270,804 discloses a color display system utilizing reflective light valves wherein light is first split into its two axes of polarization by a beam splitting cube. Light in one of the polarizations is directed to a color splitting-recombining prism assembly where each color is separated, reflected from a light valve, recombined and redirected through the polarizing beam splitter. U.S. Pat. No. 4,687,301 is directed to a full color projector utilizing a liquid filled three color separating-recombining prism assembly. A glass three color prism assembly is disclosed in U.S. Pat. No. 4,687,301.
In a system using reflective light valves, the illuminating light beam and the reflected imaging beam must share a portion of the light path through the optical assembly, introducing considerable complexity and unwanted light scattering. Thus, there is a need for an arrangement aimed at minimizing the common light path for improved contrast control and simplification of optical component design.